Trump suggested the NFL is being ruined now that it's addressing brain injuries -- here's what collisions do to players

When Trump criticised NFL players for kneeling during the national anthem, he also said football was being ruined by rules that limit head injuries.

Science has shown that repeated head injuries can cause permanent harm or death.

The bigger question is whether the NFL’s efforts to protect players are enough.

President Donald Trump took aim at the NFL at an Alabama campaign rally on Friday, criticising players for kneeling during the national anthem — a peaceful protest meant to draw attention to violence committed against people of colour by police.

One of the first players to begin these protests, Eric Reid, recently wrote that he and quarterback Colin Kaepernick chose kneeling as a way to draw attention to the injustice “because it’s a respectful gesture.” But Trump condemned that quiet protest, suggesting NFL team owners should say: “Get that son of a b—- off the field right now, out. He’s fired. He’s fired!”

Following the president’s comments and tweets, a number of NFL players and teams chose to kneel and link arms during the national anthem last weekend in a display of unity. Commissioner Roger Goodell asserted that players had the right to protest.

But Trump also bashed the NFL for another reason: He said the league’s efforts to prevent brain injuries by restricting certain hits was making the game less enjoyable.

“Because you know, today if you hit too hard — 15 yards! Throw him out of the game. They had that last week, I watched for a coupled of minutes. Two guys, just really, beautiful tackle. Boom! 15 yards. The referee goes on television, his wife’s so proud of him. They’re ruining the game! They’re ruining the game,” he said.

The NFL and other football leagues (down to the youth level) have started to crack down on certain types of aggressive hits to the head. And there’s good reason to think that limiting head injuries could make permanent brain injury less likely.

Of course, Trump isn’t known for his healthy lifestyle — his diet and fitness practices contradict the advice of many doctors, nutritionists, and trainers. So here’s why some of the violence the president seems to enjoy has been eliminated, and why some experts say such rules probably don’t go far enough.

When the brain slams against the skull

Most of the changes that football leagues made in recent years were designed to limit concussions, which happen when a collision causes the brain to slam against the inside of the skull, causing a mild traumatic brain injury.

There’s a lot that doctors still don’t know about concussions, Dr. Chad Asplund, medical director of athletics sports medicine at Georgia Southern University, previously told Business Insider. But we do know that limiting them is a good idea.

The CDC reports that concussions negatively affect memory, reasoning, sight, balance, and language abilities. They can be linked to depression, anxiety, aggression, personality changes, and an increased risk of Alzheimer’s, Parkinson’s, and other brain disorders. Repeated brain injuries can be “catastrophic or fatal” if they happen in a short period of time, according to the CDC.

To cut down on concussion rates, the NFL moved kickoffs to the 35-yard-line and later moved the starting point for a touchback (when the kickoff is downed in the end zone instead of returned) from the 20-yard-line to the 25. These modifications were intended to cut down on kickoff returns, which are particularly dangerous since players build up speed as they run at each other from across the field. The NFL has also banned hits that use the top of the helmet as a weapon, and prioritised the enforcement of rules against hits targeting the head.

Whether or not these efforts are working is unclear. NFL concussion rates in 2015 went up significantly, though they’d decreased after new rules were enacted in 2012 (it’s also possible that more vigorous screening uncovered more concussions). Steps taken in youth football leagues have reportedly decreased concussion rates significantly.

And whether these efforts will curb the long-term brain injury problems that plague the NFL is another question entirely.

Elsa/Getty ImagesAaron Hernandez was found to have severe CTE when his brain was examined after his suicide.

Chronic traumatic encephalopathy

A large part of the modern controversy about football has to do with CTE, which stands for chronic traumatic encephalopathy. CTE is a degenerative brain disease strongly linked to repeated blows to the head.

One recent study published in the Journal of the American Medical Association revealed that out of 202 deceased American football players, 177 showed signs of CTE. The results were even more stark for former NFL players — 110 out of 111 of them in the study (99%) were found to have the disease, which can only be diagnosed after death.

That high percentage should be taken with a note of caution, however, since the players were likely enrolled in the study because of suspicions that they had CTE. When alive, all of these individuals showed signs of the brain disorder, including problems with mood, memory, judgment, aggressive behaviour, and dementia. Symptoms like these tend to become more severe the longer someone played football, according to that study. The most dramatic symptoms, like dementia, were most likely to show up in the most severe cases.

Inside the brain, CTE’s signs include an abnormal protein called tau that gets built up inside brain tissue, which shows signs of degeneration. These indicators tend to appear in parts of the brain linked to cognition, working memory, planning, emotional control, and aggression. The disease was first described as dementia pugilistica in 1973, after a study of deceased former boxers showed all had similar signs of neurodegeneration.

Recently, former NFL player Aaron Hernandez — who killed himself at age 27 while serving time for a murder conviction — was found to have severe CTE similar to that found in the brains of former players who lived into their 60s.

CTE and the NFL

Concerns about the links between football and CTE are well established — the NFL has even been accused by former players of covering up information about the risks of concussions, head injuries, and CTE. The league eventually settled a $US1 billion lawsuit in which thousands of former players accused the NFL of concealing those risks. The NFL has now acknowledged the link between playing football and developing CTE.

Preventing or limiting concussions may be a step towards addressing that problem. But current rules may not be sufficient. Some experts think CTE could be caused by repeated blows to the head, not just concussions. A recent study found that even young athletes exposed to medium levels of physical contact (playing sports like soccer and basketball) showed signs of brain changes. Young football players who have never suffered concussions show signs of brain injury as well.

Regardless of the exact mechanisms that cause CTE, criticising efforts to limit brain injuries is irresponsible, insensitive, and cruel.

Trump’s statements implied that entertainment value may be more important than an individual’s health. But there’s a long history of protective rules in modern gladiatorial sports. Removing those for the sake of entertainment increases the chances that people will be permanently harmed or even killed.